Beer Lesson: Wild Yeasts

Question: Once feared by brewers and wine makers alike as a contaminating factor, brettanomyces, a wild yeast commonly referred to as Brett, is showing up more frequently as an ingredient in craft-brewing concoctions. But why?

Answer: All beers used to have Brett—just not on purpose, hence the “wild” designation. Before stainless-steel tanks helped regulate the beer-making process, suds were brewed in wooden barrels where Brett would take shelter in the porous surface of the wood and join in on the fun. Brewers were clueless about the uninvited guests and added saccharomyces, or brewer’s yeast, to ferment and flavor their beers. The result was unpredictable, but often similar to what we now consider a sour beer. Back then, it was just beer. In short, no two Brett-influenced beers were quite alike. Once they knew what was going on, brewers gladly removed Brett from the brewing process and standardized operations (with notable expections, like Lambic beers, which use a spontaneous brewing method and welcome outside contamination).

Until now. Brewers, like Crooked Stave's Chad Yakobson are not only using the tempermental yeast, they embrace it. Since the first Crooked Stave batch in January 2011, Yakobson has created aboout a dozen beers, all using Brett. “Now that I’m using the same yeast time and time again, I’m actually seeing the same results," Yakobson says. "Unique characteristics in each one and little twists, but quite similar stuff. I might actually say that now I don’t see it being so wild anymore.”

While each strain of yeast has it’s own unique characteristics, expect to find tart and fruity flavors in Brett beers, as well as almost “horsey” or earthy, musty flavors. Most importantly, expect to have plenty of Brett beers to try soon. “There’s so much want—there’s so much interest in these beers—but there’s so little knowledge,” Yakobson says. “There wasn’t this much interest in IPAs when IPAs took off because people knew how to make IPAs. But this was so different. So I think it’ll continue to grow. I think this is just the beginning.”